RANGE OF AVAILABLE REPLACEMENT SYSTEMS
ENVIROSUN SOLAR HOT WATER INSTALLATION
Envirosun THX300/60 Installation Brisbane & Gold Coast
JR Gas & Water supplies and installs the Envirosun THX300/60 solar hot water system across eligible Brisbane and Gold Coast service areas. It is a roof-mounted thermosiphon solar system designed around a closed-circuit configuration, with the storage tank and solar collectors installed together on the roof.
JR's existing THX300/60 product specification identifies this model as a 300 litre roof-mounted solar system with approximately 6m² of collector area. Unlike an open-circuit thermosiphon system, the THX design uses an indirect closed solar circuit intended to provide additional protection in freezing conditions and in locations where water quality can make direct circulation less suitable.
The THX300/60 is therefore a more specialised solar hot water installation than a basic roof-mounted system. Roof structure, usable roof area, orientation, access, lifting requirements, plumbing layout and the selected booster arrangement all need to be considered before installation.
Envirosun THX300/60 at a glance: JR lists the THX300/60 as a roof-mounted closed-circuit thermosiphon solar hot water system with approximately 300L storage and a larger solar collector configuration. It is intended for properties where a roof-mounted tank is practical and where the additional freeze and water-quality protection of Envirosun's THX closed-circuit design is desirable. JR installs the system across eligible Brisbane and Gold Coast areas subject to roof, access, structural and plumbing suitability.
Envirosun THX300/60 Supply & Installation at a Glance
Product Type
Closed-circuit roof-mounted thermosiphon solar hot water system.
Storage
JR's existing product specification identifies the THX300/60 as a nominal 300L-class solar hot water system.
Solar Configuration
JR lists the THX300/60 with the larger 60-series collector arrangement and approximately 6m² of solar collection.
Installation Area
Professional supply and installation across eligible Brisbane and Gold Coast service areas.
Who Is the Envirosun THX300/60 Best For?
Roof-Mounted Solar Buyers
The THX300/60 is intended for households wanting the storage tank and solar collectors installed together on the roof rather than using a ground-level split-system tank.
Properties Needing Closed-Circuit Protection
Envirosun's THX design uses a closed solar circuit intended to improve protection against freezing and collector fouling, making it worth considering where those operating conditions matter.
Stronger Solar Collection
JR's THX300/60 configuration is positioned with greater collector area than the smaller 40-series arrangement, making solar collection capacity an important reason to consider this version.
PRODUCT SUITABILITY
Is the Envirosun THX300/60 Right for My Home?
A Good Choice If...
You want a roof-mounted thermosiphon system, have sufficient usable roof area, prefer a closed-circuit solar design and want a larger solar collection arrangement than the smaller THX configuration.
Consider Another Option If...
Your roof is unsuitable for the combined weight of the tank and collectors, safe access is difficult, roof space is limited or you would prefer the storage cylinder to remain at ground level. An active split solar or heat pump system may be more practical on some properties.
JR Should Check First If...
You are changing from a ground-mounted system, the existing roof structure is uncertain, the unit requires relocation, roof access is restricted, or the existing booster and plumbing arrangements differ substantially from the new installation.
What Household Is the Envirosun THX300/60 Suited To?
The THX300/60 is built around a 300L-class roof-mounted storage system and is positioned by JR for family-sized solar hot water demand. However, occupant numbers should not be determined from tank capacity alone.
Actual suitability depends on shower duration and flow rates, number of bathrooms, bath use, simultaneous demand, dishwasher and laundry habits, the timing of hot water use, available solar energy and how often the booster needs to operate.
Homes with concentrated morning or evening demand can require more effective hot water capacity than households with the same number of occupants using hot water throughout the day. JR should therefore match the system to the home's real usage pattern rather than relying on a simple people-to-litres calculation.
How Does the Envirosun THX300/60 Work?
The THX range uses the thermosiphon principle. The storage tank is positioned above the solar collectors on the roof. As the solar collectors heat the solar circuit, warmer fluid naturally rises while cooler fluid moves down toward the collectors, allowing circulation without the active circulation pump used by a split solar system.
The important difference with the THX design is that the collector circuit is closed rather than allowing the household's potable water to circulate directly through the collectors. Envirosun describes the THX as an indirect system with a separate jacket chamber, providing additional freeze protection and suitability for areas where poor water quality could otherwise increase collector fouling.
The process is therefore: sunlight heats the collector circuit → thermosiphon circulation transfers heat into the storage system → the tank stores hot water for household use → the booster supplies supplementary heating when solar input is insufficient.
Key Features of the Envirosun THX300/60
Closed-Circuit Solar Design
The THX range isolates the solar collector circuit from household water, providing a different operating arrangement from Envirosun's standard open-circuit TS systems.
Freeze Protection
Envirosun specifically positions its THX indirect system for improved freeze protection in colder conditions.
Water-Quality Protection
The closed-circuit configuration also reduces direct exposure of the solar collectors to household water, which Envirosun identifies as beneficial in areas with poorer water quality.
Roof-Mounted Thermosiphon Layout
The storage tank and solar collectors are installed together on the roof, eliminating the need for the active circulation pump used by a split solar system.
Larger Solar Collection
JR's existing THX300/60 configuration is listed with the larger 60-series solar collector arrangement for increased available collection area.
Boosted Hot Water
The system can incorporate supplementary boosting so hot water remains available during periods when solar input alone does not meet household demand.
Envirosun THX300/60 Specifications
| Specification | Details |
|---|---|
| Brand | Envirosun |
| JR Product Model | THX300/60 |
| Product Type | Closed-circuit thermosiphon solar hot water system |
| Installation Type | Roof-mounted tank and collectors |
| Storage Class | 300L class, as listed by JR |
| Collector Configuration | 60-series / approximately 6m² as currently listed by JR |
| Solar Circuit | Indirect closed circuit |
| Primary Energy Source | Solar |
| Backup Heating | Booster configuration dependent on selected system |
| Freeze Protection | Closed-circuit THX design |
| Water-Quality Protection | Closed circuit reduces direct collector exposure to potable water |
Model verification note: JR currently lists this product as the THX300/60. Envirosun's present public product range lists the THX300/40 rather than a THX300/60, so current manufacturer documentation should be confirmed against the exact supplied SKU before adding model-specific CER codes, system weights, collector quantity, boost capacity or dimensions to the commercial specification area.
INSTALLATION REQUIREMENTS
What Is Required to Install the Envirosun THX300/60?
A roof-mounted thermosiphon system places both the storage cylinder and solar collection equipment on the roof, so installation requirements differ substantially from a ground-mounted electric tank or active split solar system.
Suitable roof area for the complete system
Suitable roof structure and mounting conditions
Safe roof access for installation work
Appropriate roof pitch and collector position
Suitable hot and cold water pipework
Compliant pressure and safety valves
Suitable relief and drainage arrangements
Correct booster configuration
Electrical or gas services where applicable
Tempering where required
Safe lifting and positioning of roof-mounted equipment
Licensed installation and commissioning
Roof construction, height, pitch, access, lifting requirements, existing system layout and booster configuration can materially change installation scope.
What's Included With Envirosun THX300/60 Installation?
Standard Installation
The selected JR installation package covers the applicable labour and materials shown in the live product selector. Depending on the package, this can include removal of the existing system, roof positioning, plumbing connections, applicable valves and connection of the selected booster arrangement.
Compliance & Commissioning
The installed system is connected, checked and commissioned for correct operation, including plumbing connections, safety components, solar operation and booster functionality where applicable.
Possible Additional Work
Difficult access, elevated roofs, specialised lifting, structural work, non-standard mounting, relocation, extended pipework, electrical work or significant changes to the existing installation may require additional work or a separate quote.
How Much Does Envirosun THX300/60 Installation Cost?
Current supplied-and-installed pricing should be taken from the live JR product and installation selector above. This keeps the displayed Envirosun THX300/60 installation price aligned with the current product cost, package selection and any applicable installation options.
Final installation cost can vary with roof height, safe access, lifting requirements, replacement type, existing plumbing, valves, booster configuration, electrical or gas work, relocation and any structural or mounting work required.
A straightforward replacement of a compatible roof-mounted solar system may require less alteration than converting a ground-mounted electric, heat pump or split solar installation to a thermosiphon system.
BRISBANE INSTALLATION
Envirosun THX300/60 Installation Brisbane
JR Gas & Water supplies and installs the Envirosun THX300/60 across eligible Brisbane service areas. For an existing roof-mounted solar replacement, the first installation checks are the roof condition, system position, access, existing water connections and whether the replacement can practically use the current layout.
When converting from ground-level electric storage, heat pump or split solar, the installation changes more substantially because the new system places its storage tank and collectors on the roof. The available roof area, mounting position, lifting method, plumbing route and booster services therefore become central to the installation assessment.
JR also services eligible surrounding areas including Logan, Ipswich, Moreton Bay and Redlands, with final availability and installation scope dependent on the property.
GOLD COAST INSTALLATION
Envirosun THX300/60 Installation Gold Coast
Gold Coast THX300/60 installations require a roof that can practically accommodate the combined thermosiphon system and allow safe access for lifting, mounting and future servicing. Roof configuration matters more with a roof-mounted tank than it does with a split solar system where the storage cylinder stays on the ground.
Where an older thermosiphon solar system is being replaced, JR can assess whether the existing position and plumbing remain suitable. Renovations, system relocations and conversions from other technologies can require a more extensive installation because water services and booster arrangements may need to be altered to suit the roof-mounted configuration.
The objective is to match the THX system to a property that genuinely suits its installation method rather than selecting it only because of its solar performance.
Can the Envirosun THX300/60 Replace My Existing System?
Replacing Roof-Mounted Solar
This is generally the most direct replacement scenario, but roof condition, dimensions, mounting points, plumbing, booster arrangements and safe access still need to be confirmed.
Replacing Split Solar
A split solar system has its tank at ground level, so converting to the THX layout moves the storage component to the roof and can require significant plumbing and mounting changes.
Replacing Electric or Heat Pump Hot Water
Conversion can be possible on suitable properties, but it is not a like-for-like replacement. Roof-mounted solar equipment, new pipework and the applicable booster arrangement must be incorporated into the installation.
Replacing Another Brand
The existing product does not need to be Envirosun. Compatibility depends more on the roof, available space, plumbing, services and mounting requirements than the previous brand.
How Efficient Is the Envirosun THX300/60?
The THX300/60 is intended to use collected solar energy as its primary source of water heating, with the booster operating when available solar energy does not meet household demand.
The larger collector arrangement listed by JR is intended to provide greater solar collection capacity than a smaller collector configuration. However, actual purchased-energy savings vary with roof orientation, shading, weather, hot water consumption, incoming water temperature, booster settings and household usage.
For that reason, a fixed running-cost or percentage-saving claim should not be applied to every property. The important efficiency consideration is whether the system is correctly sized and installed on a roof that receives useful solar exposure.
THX Closed Circuit vs Standard Open Circuit Solar
| Feature | THX Closed Circuit | Open Circuit Thermosiphon |
|---|---|---|
| Tank Location | Roof mounted | Roof mounted |
| Collector Location | Roof mounted | Roof mounted |
| Circulation Principle | Thermosiphon | Thermosiphon |
| Solar Circuit | Indirect closed circuit | Household water circulates through solar circuit |
| Freeze Protection | THX design specifically intended for improved freeze protection | Depends on system design and installation conditions |
| Water Quality | Closed circuit reduces direct collector exposure to household water | Collectors are exposed to circulating household water |
| Best Reason to Consider | Closed-circuit protection where site conditions justify it | Simpler direct thermosiphon configuration where suitable |
The THX design is not automatically necessary for every Brisbane or Gold Coast property. Its closed-circuit configuration is most valuable where the operating conditions make the additional freeze or water-quality protection relevant.
COMMON QUESTIONS
Envirosun THX300/60 Installation FAQs
How much does Envirosun THX300/60 installation cost?
Current supplied-and-installed pricing is shown in the live product selector above. Final cost depends on roof access, lifting requirements, mounting conditions, the existing system, pipework, valves, booster services and any non-standard installation work.
Can JR install the Envirosun THX300/60 in Brisbane?
Yes, across eligible Brisbane service areas where the roof, access, mounting conditions, plumbing and booster arrangement are suitable for the thermosiphon installation.
Can JR install the THX300/60 on the Gold Coast?
Yes. JR installs roof-mounted solar hot water systems across eligible Gold Coast areas subject to the roof and property meeting the applicable installation requirements.
What makes the THX system different from normal roof-mounted solar?
The THX uses an indirect closed solar circuit rather than circulating household water directly through the solar collectors. Envirosun positions this design for greater freeze and collector-fouling protection.
Does the Envirosun THX300/60 use glycol?
The THX is a closed-circuit indirect system designed around a separate solar heat-transfer circuit. The exact heat-transfer fluid and service requirements should follow the documentation supplied with the particular THX300/60 system being installed.
Is the THX300/60 better for poor water quality?
Envirosun states that its THX closed-circuit systems are suitable for areas with poor water quality because household water does not circulate directly through the solar collector circuit.
Can the THX300/60 replace another brand of solar hot water system?
Potentially, yes. Suitability depends on roof space, structural and mounting conditions, access, plumbing and booster compatibility rather than the previous brand alone.
Can it replace a ground-mounted hot water system?
It can on a suitable property, but conversion is more involved because the THX storage tank and collectors need to be installed on the roof and connected to the home's existing water and booster services.
Does the THX300/60 need a circulation pump?
No active solar circulation pump is normally required for the roof-mounted thermosiphon principle. Heat movement through the solar circuit occurs through natural thermosiphon circulation.
What roof checks are important before installation?
Usable roof space, structural suitability, roof pitch, system position, solar access, mounting conditions and safe installer access all need consideration before a roof-mounted tank and collector system is installed.
Can the THX300/60 be electrically or gas boosted?
The selected booster arrangement needs to match the exact supplied system and the services available at the property. JR should confirm the booster configuration before installation rather than assuming an existing gas or electrical setup can be reused unchanged.
What happens if my roof does not suit the THX300/60?
A different solar layout or another hot water technology may be more appropriate. An active split solar system keeps the tank at ground level, while a heat pump can avoid roof-mounted solar collectors altogether.
Envirosun THX300/60 Warranty and Maintenance
Manufacturer Warranty
Envirosun currently publishes a 10-year product and 2-year labour warranty for qualifying residential original owner-occupiers for products purchased from 26 June 2026, subject to the manufacturer's current terms, exclusions and product eligibility.
JR Lifetime Warranty Eligibility
The current JR THX300/60 listing identifies the product as Lifetime Warranty eligible. JR warranty coverage is separate from the Envirosun manufacturer warranty and remains subject to JR's applicable terms.
Ongoing Maintenance
Roof-mounted solar systems should remain accessible for inspection and servicing. The tank, collectors, valves, closed solar circuit, heat-transfer medium and booster components should be maintained in accordance with the documentation supplied for the installed system.
Why Choose JR Gas & Water for Envirosun THX300/60 Installation?
Roof-mounted solar hot water requires practical installation experience because the product cannot be assessed independently of the roof. Access, lifting, mounting, plumbing, booster configuration and commissioning all determine whether the finished installation is appropriate.
JR Gas & Water provides hot water supply and installation across Brisbane, the Gold Coast and surrounding South East Queensland service areas. The focus with the THX300/60 is matching the system to a property that genuinely suits a roof-mounted closed-circuit thermosiphon installation rather than selecting the product solely from a specification sheet.
COMPARE YOUR OPTIONS
Compare Solar Hot Water Systems & Installation Options
Before choosing the THX300/60, compare whether the property is best suited to roof-mounted thermosiphon solar, active split solar or another hot water technology. The right choice depends on roof suitability, available space, hot water demand, existing services and the complexity of the replacement.
Use the current JR main navigation to compare available Hot Water Systems, Solar Hot Water Systems and Envirosun hot water options.
READY TO INSTALL
Install the Envirosun THX300/60 With JR Gas & Water
The Envirosun THX300/60 is positioned by JR as a high-capacity roof-mounted solar option using Envirosun's closed-circuit THX thermosiphon design. Its main distinction is not simply storage capacity: it is the combination of roof-mounted solar operation with additional freeze and water-quality protection from the indirect collector circuit.
The critical installation checks are roof suitability, access, mounting conditions, lifting requirements, plumbing and booster compatibility. Where the property fits the available online installation conditions, choose the appropriate package through the live product selector above. More complex replacements, relocations or technology conversions should follow JR's quote pathway.
ZipPay – 6-Month Interest-Free on All Products
ZipPay allows you to buy now and pay later, offering flexible, interest-free payments for up to 6 months on all JR products. It’s easy to set up, and you can customize your repayment schedule to suit your budget. Payments can be made weekly, fortnightly, or monthly, with a $6 fee if the balance isn’t paid off by the due date.
Humm – Up to 12 Months Interest-Free
Humm provides interest-free payment plans on purchases up to $30,000, perfect for both small and large buys. For items over $2,000, you can spread payments over 12 months. Humm also offers flexibility in scheduling payments based on when you get paid
Afterpay – 8 Weeks, No Interest
With Afterpay, spread the cost of purchases across four equal installments, due every two weeks, over an 8-week period. There’s no interest, and as long as payments are made on time, there are no fees. Perfect for purchases between $100 and $1,500
Plenti Finance – For Reclaim Systems Only
Plenti Finance is available exclusively for Reclaim Energy systems. This option offers tailored repayment terms with competitive interest rates, helping make eco-friendly choices more affordable. For more detailed information on Plenti’s terms and eligibility for Reclaim systems, visit the Reclaim Energy finance page
Brand - Envirosun
Model Number - THX300/60
Volume - 300L
Width - 2150mm
Height - 650mm
Manufactured In -
Cylinder/ Heat Exchange Material - Stainless Steel
Cylinder/Heat-Exchange Warranty - 7 Years
Noise Level - NAdBa
Dry Weight - 59kg
Energy Source - Solar
Wifi Controller Built in or Compatible -
Built In Timer - No
LED/LCD Status Indicator -
Coefficient of Performance (COP) -
If you're in Queensland and considering a new electric hot water system, JR Gas & Water is the company to choose. Here's why:
Experience and Expertise: JR Gas & Water has over 10 years of experience in the gas and plumbing industry. Their team of licensed and insured professionals is highly skilled and knowledgeable about all aspects of electric hot water system installation, maintenance, and repair. They can provide expert advice on the best system for your needs and ensure a smooth installation process.
Quality Products: JR Gas & Water uses only high-quality products from trusted brands to ensure your electric hot water system is reliable and efficient. They also offer a range of options to suit different budgets and requirements.
Competitive Pricing: JR Gas & Water offers competitive pricing for their electric hot water systems, ensuring that you get a great value for your investment. They also provide a detailed quote upfront, so there are no surprises or hidden costs.
Customer Service: JR Gas & Water is committed to providing excellent customer service. They are always available to answer any questions or concerns you may have and are committed to ensuring your satisfaction.
Local Business: JR Gas & Water is a locally owned and operated business in Queensland. By choosing them for your electric hot water installation, you are supporting a local business and contributing to the local economy.
Warranty and Guarantee: JR Gas & Water provides a warranty and guarantee on all their products and services, giving you peace of mind knowing that your system is covered in case of any issues.
Energy Efficiency: Electric hot water systems can be energy efficient, and JR Gas & Water can help you choose the right system for your needs. They can provide advice on energy-saving features and options, such as timers and thermostats, to help you save on your energy bills.
Safety: JR Gas & Water is committed to safety and ensuring that all installations are done to the highest safety standards. They are also familiar with local safety regulations and requirements, ensuring that your electric hot water system is installed safely and in compliance with all relevant codes.
JR Gas & Water is a reliable and experienced choice for your electric hot water system installation in Queensland. With a commitment to quality products, competitive pricing, excellent customer service, and safety, they can help you make the switch to a more efficient and cost-effective solution for your hot water needs. Contact them today to learn more about their services and how they can help you.
JR GAS & WATER INSTALLER ASSESSMENT
Our Installer Verdict
This is the part of the product page we consider most important. It is not based on manufacturer marketing or homeowner-facing specifications. This is our own assessment of what the product is actually like for our team to install, commission, service and support.
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